Ⅱ-Ⅵ族化合物中原子间两体及三体相互作用势的理论研究

First-principles study on the two and three-body interatomic potentials of Ⅱ-Ⅵ compounds

采用基于密度泛函理论和Hartree-Fork的第一性原理方法,计算了CdS、CdSe、CdTe、HgTe等Ⅱ-Ⅵ族化合物中原子间的两体及三体相互作用势,分析了基组及计算方法的选择对计算结果的影响。采用Lennard-Jones、Born-Mayer和Morse势函数对两体相互作用势进行拟合,得到相应的拟合参数及误差值,结果表明普遍应用于共价分子的Morse势也同样适用于Ⅱ-Ⅵ族原子二聚体。考虑到多体相互作用势必须考虑角度因素,采用Stilling-Weber势函数对三体势进行了拟合研究,结果亦较为理想。

First-principles method based on DFT and HF are used to calculate the two-body and three-body inter-atomic potentials of Ⅱ-Ⅵ compounds CdS,CdSe,CdTe and HgTe.The influence of the basis sets and the various approximate methods to the results are analyzed.Lennard-Jones,Born-Mayer and Morse potential function are used to fit the two-body potential energy curve.The results show that Morse potential function applied in covalent molecules is also suitable for the dimmers of Ⅱ-Ⅵ compounds.Since the angel effect must be considered in many-bodies＇ interactions,Stilling-Weber potential function is used to fit the three-body potential energy curve and the results are ideal.